The energy transfer mechanism in Pr super(3+) and Yb super(3+) codoped beta -NaLuF sub(4) nanocrystals

• Published in: Physical chemistry chemical physics : PCCP Vol. 16; no. 20; pp. 9289 - 9293
• Main Authors: Xiang, Guotao, Zhang, Jiahua, Hao, Zhendong, Zhang, Xia, Pan, Guohui, Luo, Yongshi, Lue, Shaozhe, Zhao, Haifeng
• Format: Journal Article
• Language: English
• Published: 01.04.2014
• Subjects: Decay; Diffraction; Doping; Energy transfer; Ion concentration; Morphology; Nanostructure; Quantum efficiency
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c4cp01184h

The Pr super(3+) and Yb super(3+) codoped beta -NaLuF sub(4) hexagonal nanoplates with a size of 250 nm 110 nm were synthesized by a solvothermal process. X-Ray diffraction and scanning electron microscopy were used to characterize the crystal structure and morphology of the materials. The visible and near infrared spectra as well as the decay curves of Pr super(3+): super(3)P sub(0) level were used to demonstrate the energy transfer from Pr super(3+) ions to Yb super(3+) ions. The downconversion phenomenon has been observed under the direct excitation of the super(3)P sub(2) level of Pr super(3+). According to the analysis of the dependence of the initial transfer rate upon Yb super(3+) ion concentration, it indicates that the ET from Pr super(3+) ions to Yb super(3+) ions is only by a two-step ET process when the Yb super(3+) concentration is very low; however, with the increase of the Yb super(3+) concentration, a cooperative ET process occurs and gradually increases; when the Yb super(3+) ion concentration increases to 20 mol%, the ET from Pr super(3+) ions to Yb super(3+) ions occurs only by the cooperative ET process. When the doping concentration of Yb super(3+) ions reaches 20 mol% at a fixed concentration of Pr super(3+) ions (1 mol%), the theoretical quantum efficiency is 192.2%, close to the limit of 200%. The current research has great potential in improving the conversion efficiency of silicon solar cells.